In various manufacturing and processing procedures it is desirable to measure the surface form of a material for quality control or other processing aspects. Often times such analysis is done manually however in certain applications a non-contact analysis is desirable. For example in U.S. Pat. No. 4,710,808 there is provided a means of determining the thickness of an object through the use of a differential measurement system. The system provides such measurement through the use of structured light from two sources projected along a common axis at opposite surfaces of an object. The images formed are monitored by the two sources of light which detect the distance from a feature of each of the images to a reference point. The thickness of the object is proportional to the sum of the distances if the reference point is within the sheet of material and if not, then it is the difference of the distances.
While such a system has proven very satisfactory it is desired to provide a display which provides for a three dimensional measurement of the surface of an object.